What methods are being used to reduce noise pollution?

Noise Pollution
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At times, engineers try to achieve just the right sound or noise for a particular product. The product, whether it’s a vacuum cleaner, lawnmower, or motorcycle, needs to be quiet enough so as not to cause stress, yet has to have enough sound to seem powerful. For example, muffler technology has the ability to greatly reduce the noise a motorcycle produces, yet many engineers and manufacturers feel that consumers would not purchase the product if it does not sound “powerful” enough. Hybrid automobiles are so quiet that people with limited sight have difficulties knowing that they are approaching. Engineers are developing noise generating devices for these cars to let sightless people know the location of the cars.

Since noise creates stress and can lead to other health problems, industries and governments around the world are working to reduce noise levels, especially around populated regions. One method of reducing noise pollution around airports has been rerouting airline traffic so that it passes over less-populated areas. Sound barriers have been installed along many highways to absorb and/or reflect sound away from houses built alongside the roads. In countries such as Austria and Belgium, roadways are being constructed with a material called whisper concrete that engineers claim reduces noise by 5 decibels. Finally, Swedish engineers have developed a road surface made of pulverized rubber that can reduce the noise level by as much as 10 decibels.